美国电子邮件文件管理发展与现状

The Development and Present Situation about the Document Management of the U.S. E-mail

由于对电子邮件文件地位认识不一致，导致人们在制定电子邮件政策时也存在着分歧。目前美国的电子邮件政策很少，政策制定的进展和完善程度也不一致。联合国大多数组织还没有制定出达到文件管理要求的保存与控制电子文件的方法，还没有对电子文件的鉴定、获取、管理实施指导，还存在着“政策真空”。文章列举有关方面关于电子邮件政策的研究探讨、报告述评，对我们在研究制订相关政策时，具有借鉴意义。

Because of the difference in understanding documental status of E-mail, there is a difference in people's making E-mail policy. At present there are few E-mail policies in the United States, and the degree of progress and perfect in policy making is also different. Most organizations of The U.N have not worked out a method that meets the management requirement of document in preserving and controlling the E-mail, and have not carried out a guidance to the appraisal, acquisition and management of the E-mail. There are no such policies. This article enumerates studying, exploring, report and commentary about E-mail policy from concerned organizations, which has a significance of using for reference in our studying and making related policy.g regions by using a motion detector. Then, the motion estimation is performed in moving regions. In order to eliminate the inherent shortcomings of classical block matching algorithm, a variable size block matching technique is applied in the proposed algorithm. In order to retain the true motion vectors in regions prone to mismatch, a multi candidate pre screening method is used to record all the possible motion vectors and then true motion vector is most likely selected according to the correlation of motion vectors between the neighboring blocks. The experimental results show that this algorithm may produce reliable and coherent motion vectors.